Cod sursa(job #3197546)
Utilizator | Data | 27 ianuarie 2024 09:46:04 | |
---|---|---|---|
Problema | Aria | Scor | 70 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.45 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream fin("aria.in");
ofstream fout("aria.out");
const int MAXN = 1e5;
double X[MAXN + 5], Y[MAXN + 5];
int N;
long double aria;
int main()
{
fin >> N;
for(int i = 0; i < N; ++i)
fin >> X[i] >> Y[i];
X[N] = X[0],
Y[N] = Y[0];
for(int i = 0; i < N; ++i) {
aria += X[i] * Y[i + 1] - X[i + 1] * Y[i];
}
fout << fixed << setprecision(5) << aria / 2.0;
return 0;
}